config: pass source to config_parser_event_fn_t

..so that the callback can use a "struct config_source" parameter
instead of "config_reader.source". "struct config_source" is internal to
config.c, so we are adding a pointer to a struct defined in config.c
into a public function signature defined in config.h, but this is okay
because this function has only ever been (and probably ever will be)
used internally by config.c.

As a result, the_reader isn't used anywhere, so "struct config_reader"
is obsolete (it was only intended to be used with the_reader). Remove
them.

Signed-off-by: Glen Choo <chooglen@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

config.c

@@ -66,40 +66,6 @@ struct config_source {
 };
 #define CONFIG_SOURCE_INIT { 0 }
 
-struct config_reader {
-	/*
-	 * These members record the "current" config source, which can be
-	 * accessed by parsing callbacks.
-	 *
-	 * The "source" variable will be non-NULL only when we are actually
-	 * parsing a real config source (file, blob, cmdline, etc).
-	 */
-	struct config_source *source;
-};
-/*
- * Where possible, prefer to accept "struct config_reader" as an arg than to use
- * "the_reader". "the_reader" should only be used if that is infeasible, e.g. in
- * a public function.
- */
-static struct config_reader the_reader;
-
-static inline void config_reader_push_source(struct config_reader *reader,
-					     struct config_source *top)
-{
-	top->prev = reader->source;
-	reader->source = top;
-}
-
-static inline struct config_source *config_reader_pop_source(struct config_reader *reader)
-{
-	struct config_source *ret;
-	if (!reader->source)
-		BUG("tried to pop config source, but we weren't reading config");
-	ret = reader->source;
-	reader->source = reader->source->prev;
-	return ret;
-}
-
 static int pack_compression_seen;
 static int zlib_compression_seen;
 
@@ -752,14 +718,9 @@ int git_config_from_parameters(config_fn_t fn, void *data)
 	struct strvec to_free = STRVEC_INIT;
 	int ret = 0;
 	char *envw = NULL;
-	struct config_source source = CONFIG_SOURCE_INIT;
 	struct key_value_info kvi = KVI_INIT;
 
-	source.origin_type = CONFIG_ORIGIN_CMDLINE;
-	config_reader_push_source(&the_reader, &source);
-
 	kvi_from_param(&kvi);
-
 	env = getenv(CONFIG_COUNT_ENVIRONMENT);
 	if (env) {
 		unsigned long count;
@@ -816,7 +777,6 @@ out:
 	strbuf_release(&envvar);
 	strvec_clear(&to_free);
 	free(envw);
-	config_reader_pop_source(&the_reader);
 	return ret;
 }
 
@@ -1045,7 +1005,7 @@ static int do_event(struct config_source *cs, enum config_event_t type,
 
 	if (data->previous_type != CONFIG_EVENT_EOF &&
 	    data->opts->event_fn(data->previous_type, data->previous_offset,
-				 offset, data->opts->event_fn_data) < 0)
+				 offset, cs, data->opts->event_fn_data) < 0)
 		return -1;
 
 	data->previous_type = type;
@@ -2002,8 +1962,7 @@ int git_default_config(const char *var, const char *value,
  * fgetc, ungetc, ftell of top need to be initialized before calling
  * this function.
  */
-static int do_config_from(struct config_reader *reader,
+static int do_config_from(struct config_source *top, config_fn_t fn,
-			  struct config_source *top, config_fn_t fn,
 			  void *data, enum config_scope scope,
 			  const struct config_options *opts)
 {
@@ -2016,21 +1975,17 @@ static int do_config_from(struct config_reader *reader,
 	top->total_len = 0;
 	strbuf_init(&top->value, 1024);
 	strbuf_init(&top->var, 1024);
-	config_reader_push_source(reader, top);
 	kvi_from_source(top, scope, &kvi);
 
 	ret = git_parse_source(top, fn, &kvi, data, opts);
 
-	/* pop config-file parsing state stack */
 	strbuf_release(&top->value);
 	strbuf_release(&top->var);
-	config_reader_pop_source(reader);
 
 	return ret;
 }
 
-static int do_config_from_file(struct config_reader *reader,
+static int do_config_from_file(config_fn_t fn,
-			       config_fn_t fn,
 			       const enum config_origin_type origin_type,
 			       const char *name, const char *path, FILE *f,
 			       void *data, enum config_scope scope,
@@ -2049,7 +2004,7 @@ static int do_config_from_file(struct config_reader *reader,
 	top.do_ftell = config_file_ftell;
 
 	flockfile(f);
-	ret = do_config_from(reader, &top, fn, data, scope, opts);
+	ret = do_config_from(&top, fn, data, scope, opts);
 	funlockfile(f);
 	return ret;
 }
@@ -2057,8 +2012,8 @@ static int do_config_from_file(struct config_reader *reader,
 static int git_config_from_stdin(config_fn_t fn, void *data,
 				 enum config_scope scope)
 {
-	return do_config_from_file(&the_reader, fn, CONFIG_ORIGIN_STDIN, "",
+	return do_config_from_file(fn, CONFIG_ORIGIN_STDIN, "", NULL, stdin,
-				   NULL, stdin, data, scope, NULL);
+				   data, scope, NULL);
 }
 
 int git_config_from_file_with_options(config_fn_t fn, const char *filename,
@@ -2072,9 +2027,8 @@ int git_config_from_file_with_options(config_fn_t fn, const char *filename,
 		BUG("filename cannot be NULL");
 	f = fopen_or_warn(filename, "r");
 	if (f) {
-		ret = do_config_from_file(&the_reader, fn, CONFIG_ORIGIN_FILE,
+		ret = do_config_from_file(fn, CONFIG_ORIGIN_FILE, filename,
-					  filename, filename, f, data, scope,
+					  filename, f, data, scope, opts);
-					  opts);
 		fclose(f);
 	}
 	return ret;
@@ -2105,7 +2059,7 @@ int git_config_from_mem(config_fn_t fn,
 	top.do_ungetc = config_buf_ungetc;
 	top.do_ftell = config_buf_ftell;
 
-	return do_config_from(&the_reader, &top, fn, data, scope, opts);
+	return do_config_from(&top, fn, data, scope, opts);
 }
 
 int git_config_from_blob_oid(config_fn_t fn,
@@ -2198,8 +2152,7 @@ int git_config_system(void)
 	return !git_env_bool("GIT_CONFIG_NOSYSTEM", 0);
 }
 
-static int do_git_config_sequence(struct config_reader *reader,
+static int do_git_config_sequence(const struct config_options *opts,
-				  const struct config_options *opts,
 				  const struct repository *repo,
 				  config_fn_t fn, void *data)
 {
@@ -2299,7 +2252,7 @@ int config_with_options(config_fn_t fn, void *data,
 		ret = git_config_from_blob_ref(fn, repo, config_source->blob,
 					       data, config_source->scope);
 	} else {
-		ret = do_git_config_sequence(&the_reader, opts, repo, fn, data);
+		ret = do_git_config_sequence(opts, repo, fn, data);
 	}
 
 	if (inc.remote_urls) {
@@ -3009,7 +2962,6 @@ void git_die_config(const char *key, const char *err, ...)
  */
 
 struct config_store_data {
-	struct config_reader *config_reader;
 	size_t baselen;
 	char *key;
 	int do_not_match;
@@ -3055,11 +3007,10 @@ static int matches(const char *key, const char *value,
 		(value && !regexec(store->value_pattern, value, 0, NULL, 0));
 }
 
-static int store_aux_event(enum config_event_t type,
+static int store_aux_event(enum config_event_t type, size_t begin, size_t end,
-			   size_t begin, size_t end, void *data)
+			   struct config_source *cs, void *data)
 {
 	struct config_store_data *store = data;
-	struct config_source *cs = store->config_reader->source;
 
 	ALLOC_GROW(store->parsed, store->parsed_nr + 1, store->parsed_alloc);
 	store->parsed[store->parsed_nr].begin = begin;
@@ -3380,8 +3331,6 @@ int git_config_set_multivar_in_file_gently(const char *config_filename,
 	size_t contents_sz;
 	struct config_store_data store = CONFIG_STORE_INIT;
 
-	store.config_reader = &the_reader;
-
 	/* parse-key returns negative; flip the sign to feed exit(3) */
 	ret = 0 - git_config_parse_key(key, &store.key, &store.baselen);
 	if (ret)

config.h

@@ -72,6 +72,7 @@ enum config_event_t {
 	CONFIG_EVENT_ERROR
 };
 
+struct config_source;
 /*
  * The parser event function (if not NULL) is called with the event type and
  * the begin/end offsets of the parsed elements.
@@ -81,6 +82,7 @@ enum config_event_t {
  */
 typedef int (*config_parser_event_fn_t)(enum config_event_t type,
 					size_t begin_offset, size_t end_offset,
+					struct config_source *cs,
 					void *event_fn_data);
 
 struct config_options {
@@ -100,6 +102,10 @@ struct config_options {
 
 	const char *commondir;
 	const char *git_dir;
+	/*
+	 * event_fn and event_fn_data are for internal use only. Handles events
+	 * emitted by the config parser.
+	 */
 	config_parser_event_fn_t event_fn;
 	void *event_fn_data;
 	enum config_error_action {